This invention relates to a vehicle powered by an alternative gaseous fuel such as natural gas or hydrogen, and, more particularly, to a valve used in the fueling and fuel-distribution system of the vehicle.
Vehicles powered by alternative gaseous fuels such as natural gas or hydrogen offer the opportunity for reducing pollutant emissions while providing acceptable operating performance. An alternative fuels vehicle is generally similar in configuration to a conventional gasoline-powered vehicle, with the main difference being that the fuel system includes a pressurized-gas tank for holding the gaseous fuel instead of the conventional tank that holds liquid gasoline. The gaseous fuel is filled into the pressurized-gas tank at a maximum pressure of about 3,000-5,000 pounds per square inch, and is conveyed within the fuel system in this same pressure range.
The valving in the fuel system must be compatible with the fuel-system architecture that has been developed by the industry. The valving located at the fuel tank must permit the gaseous fuel to be filled into the fuel tank at a reasonably high rate. The filling of the fuel tank must be achieved in a time that is commercially acceptable and comparable with the filling time associated with gasoline-powered vehicles. The valving at the fuel tank must also be reliable, convenient to use, meet safety requirements of alternative-fuels vehicles, and be readily operated by an untrained consumer.
Valves have been proposed which meet some of these requirements, but not all of the requirements. There is, accordingly, still a need for an improved fuel-tank valve for use in a gas-powered alternative fuels vehicle. The present invention fulfills this need, and further provides related advantages.
The present invention provides a gaseous alternative fuels vehicle, a fuel system for use in the vehicle, and a valve used in the fuel system at the fuel tank(s). The valve has the functionality for use in a fuel system having one tank or multiple tanks. The valve allows a high rate of fuel filling. It may be changed between the open and closed positions with a rotation through a short operating arc, with a clear visual indication of whether the valve is open or closed. The valve may include a pressure release device. In one embodiment, the valve body is rotatable about its valved port even when fully tightened, so that it may be positioned at a most convenient orientation within a confined space. The valve is reliable, convenient to use, meets all safety requirements, and is easily operated by an untrained person.
In accordance with the invention, a valving system includes a valve comprising a valve body. The valve body comprises a housing having a first unvalved port, a second unvalved port, and a through-flow channel extending between the first unvalved port and the second unvalved port. The through-flow channel provides continuous gaseous communication between the first unvalved port and the second unvalved port. The valve body also includes a valved port, and a valving channel extending between the valved port and the through-flow channel. The valving channel provides valved gaseous communication between the valved port and the through-flow channel. A flow controller has a valve element within the valving channel at a valve location. The valve element is rotatably disposed to rotate about a valve element axis of rotation and includes a ball having a diametral passage therethrough disposed perpendicular to the valve element axis of rotation. An externally accessible handle extends through the valve body and is connected to the valve element. The handle rotates through an operating arc of no more than xc2xd turn to rotate the ball about the valve element axis of rotation between a closed position and an open position. Preferably, the externally accessible handle rotates exactly xc2xc turn through the operating arc to rotate the ball about the valve element axis of rotation between the closed position when the diametral passage lies perpendicular to the valving channel at the valve location and the open position when the diametral passage lies parallel to the valving channel at the valve location. There is desirably provided a ball seal between an outside surface of the ball and an inside surface of the valving channel to prevent gas leakage past the ball.
The valve may further include a pressure release device in continuous gaseous communication with the valved port. The pressure release device may be integral with the valve body. Desirably but not necessarily, the valving system includes a rotatable coupling at the valved port. The rotatable coupling permits the valve body to rotate at least one full turn about the rotatable coupling, when the rotatable coupling is tightened to an external structure.
The handle may have various convenience features. It may include a releasable detent positioned to retain the handle in the last-selected position, so that the valve may not be accidentally changed from that selected position during service. A closed-handle stop may be provided to prevent the handle from rotating past the closed position and outside of the operating arc. Similarly, an open-handle stop may be provided to prevent the handle from rotating past the open position and outside of the operating arc.
A gaseous alternative fuels vehicle comprises a vehicle body having mounted therein an engine and a gas fuel tank. A gaseous fuel supply system establishes gas communication between the engine and the gas fuel tank. The gaseous fuel supply system utilizes a valve like that described above.
The present valve is desirably used as a gaseous-fuel-shutoff valve at each of the fuel tanks of the vehicle. The use of a ball valve allows the valve to be moved between the closed and open positions with a rotation of xc2xd turn or less, allowing the valve to be switched between the closed and open positions very quickly. In the preferred design, the rotation is exactly xc2xc turn, with stops provided so that the operator of the valve may clearly see when the valve is open and when it is closed. The availability of a visual indication of whether the valve is open or closed is important in this application, because the valve may be used in an emergency to isolate its respective fuel tank. A person working in the emergency need not waste time checking whether a particular valve is closed, if it may be visually verified to be closed.
The ball valve also allows the use of a large-diameter diametral passage which permits a high rate of flow therethrough during the filling operation. The optional rotatable coupling at the valved port permits the valve body to be positioned within a confined space, so that the handle is oriented most conveniently for operation and for visual inspection of the open or closed status of the valve.
By comparison, a conventional stem-and-seat type valve, as has been proposed for use in alternative fuels vehicles for this application, requires multiple turns between the open and closed positions, and there is no visual indicator of when the valve is open or closed. The gas flow passage of the stem-and-seat type valve is much more constricted than the diametral passage of the ball valve because the stem extends through the flow passage, so that the filling operation requires a substantially longer time. The conventional stem-and-seat valves also do not have the capability for reorientation of the valve body for convenience.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. The scope of the invention is not, however, limited to this preferred embodiment.